Which Master Cylinder do I use in Rear Disc Upgrade

KG88GT · 07-17-2003, 10:39 AM

I plan on doing the 5 lug and rear disc upgrade to my 88GT. I have beed doing some searches and have not been able to determine which master cylinder I am supposed to get and what I need to do to it or what else I need to get in conjunction with the master cyliner. Any help is greatly appreciated.
Thanks
KG88GT

QuantumMotorsports · 07-17-2003, 01:04 PM

i would think your master cylinder would work, you need an adjustable proportioning valve definately. You can get these at Summit or Jegs, and they are relatively cheap. They allow you to adjust the amount of pressure that is applied to the front and rear brakes to balance them.

QuantumMotorsports · 07-17-2003, 04:39 PM

I forgot, I was also told once that if you're having a prob with pedal feel because you went to discs you can use like an 88 lincoln mark whatever master cylinder because it has a larger volume and surface area of the piston or something. Good luck.

Coupe Devil · 07-17-2003, 06:35 PM

Do the swap without changing the master cyl and without a prop valve first. My best bud bought a summit prop valve and installed it when he did his swap.. its layin in the floor of his shop now cause it was useless.

Bradley

QuantumMotorsports · 07-18-2003, 03:00 PM

man, i'll pay him for shipping if he'll ship it to me. I mean, since it's just lying on his shop floor. :-)

BLOCKER · 07-18-2003, 03:30 PM

you do not need a new master cylinder or prop valve, I did the swap, (I used a T-bird rear disc set up) the brakes work great....
good luck...

MJ86GT · 07-18-2003, 04:08 PM

Just finished the rear disc conversion on my 86GT using sn95 front and rear. I did use a prop valve from Maximum Motorsports along with the plug kit for the stock M/cylinder. Check out www.matt90gt.com site for all the info related to this swap.

What are you going to use for this swap?

jrgoffin · 07-20-2003, 12:44 PM

I added the 2-port aluminum SVO MC to mine, but it also has the 73mm front calipers. Works great, but I have also heard of others staying with the stock MC/PV (in similar fashion to the '93 Cobra) and having that work fine as well.

I wrote a real nice tech article for another site that has lots of pictures and a parts list - if anyone is interested, I'd be happy to pass it along!

Joe
jrgoffin@netzero.net

KG88GT · 07-21-2003, 10:06 AM

Just a quick post to say thanks for the help. Now it is time to hit the yards to get some parts.
Thanks again
KG88GT

07-17-2003, 10:39 AM	#1
KG88GT Registered Member Join Date: Sep 2001 Location: Pueblo, CO, USA Posts: 43	Which Master Cylinder do I use in Rear Disc Upgrade I plan on doing the 5 lug and rear disc upgrade to my 88GT. I have beed doing some searches and have not been able to determine which master cylinder I am supposed to get and what I need to do to it or what else I need to get in conjunction with the master cyliner. Any help is greatly appreciated. Thanks KG88GT

07-17-2003, 01:04 PM	#2
QuantumMotorsports Registered Member Join Date: Jul 2000 Location: Norman, Oklahoma, USA Posts: 597	i would think your master cylinder would work, you need an adjustable proportioning valve definately. You can get these at Summit or Jegs, and they are relatively cheap. They allow you to adjust the amount of pressure that is applied to the front and rear brakes to balance them. __________________ Michael Black QuantumMotorsports Norman, OK 1984 LX Hatch 306 w/ TRW forged flat toppers, Comp Cams Magnum 292H, GT40P heads w/ 3 angle valve job, .550 lift springs, Angus Racing Roller Rockers, Weiand Stealth Intake, Holley 4150 650cfm carb, MAC 1 5/8 Long Tubes, Single Chamber Flowmasters, 91' T5 w/ Pro 5.0 shifter, Turbo Coupe 8.8 Rear w/ 3.55 gears, QA1 Motorsports tubular K member, no interior except steering wheel and seat. Coming soon: 6 or 8 point cage, Fuel Cell, Weld Draglites

07-17-2003, 04:39 PM	#3
QuantumMotorsports Registered Member Join Date: Jul 2000 Location: Norman, Oklahoma, USA Posts: 597	I forgot, I was also told once that if you're having a prob with pedal feel because you went to discs you can use like an 88 lincoln mark whatever master cylinder because it has a larger volume and surface area of the piston or something. Good luck. __________________ Michael Black QuantumMotorsports Norman, OK 1984 LX Hatch 306 w/ TRW forged flat toppers, Comp Cams Magnum 292H, GT40P heads w/ 3 angle valve job, .550 lift springs, Angus Racing Roller Rockers, Weiand Stealth Intake, Holley 4150 650cfm carb, MAC 1 5/8 Long Tubes, Single Chamber Flowmasters, 91' T5 w/ Pro 5.0 shifter, Turbo Coupe 8.8 Rear w/ 3.55 gears, QA1 Motorsports tubular K member, no interior except steering wheel and seat. Coming soon: 6 or 8 point cage, Fuel Cell, Weld Draglites

07-17-2003, 06:35 PM	#4
Coupe Devil Moderator Join Date: Mar 2001 Location: Myrtle Beach SC Posts: 1,643	Do the swap without changing the master cyl and without a prop valve first. My best bud bought a summit prop valve and installed it when he did his swap.. its layin in the floor of his shop now cause it was useless. Bradley __________________ 1990 GT, 347, TFS TW Heads, TFS Cam, TFS Track heat, Twin turbos, FMIC, T5. Built Ford Tough Moderator

07-18-2003, 03:00 PM	#5
QuantumMotorsports Registered Member Join Date: Jul 2000 Location: Norman, Oklahoma, USA Posts: 597	man, i'll pay him for shipping if he'll ship it to me. I mean, since it's just lying on his shop floor. :-) __________________ Michael Black QuantumMotorsports Norman, OK 1984 LX Hatch 306 w/ TRW forged flat toppers, Comp Cams Magnum 292H, GT40P heads w/ 3 angle valve job, .550 lift springs, Angus Racing Roller Rockers, Weiand Stealth Intake, Holley 4150 650cfm carb, MAC 1 5/8 Long Tubes, Single Chamber Flowmasters, 91' T5 w/ Pro 5.0 shifter, Turbo Coupe 8.8 Rear w/ 3.55 gears, QA1 Motorsports tubular K member, no interior except steering wheel and seat. Coming soon: 6 or 8 point cage, Fuel Cell, Weld Draglites

07-18-2003, 03:30 PM	#6
BLOCKER Registered Member Join Date: Mar 1999 Location: EDMONTON, Alberta, Canada Posts: 232	you do not need a new master cylinder or prop valve, I did the swap, (I used a T-bird rear disc set up) the brakes work great.... good luck... __________________ -1988 MUSTANG COBRA GT (Canadian...eh!) -1987 Mustang LX coupe (2.3L) -1978 Harley Davidson FLH -2008 Harley Davidson Nightster 1200 -2008 Harley Davidson Night Rod Special -1997 Jaguar XK8 Convertable

07-18-2003, 04:08 PM	#7
MJ86GT Registered Member Join Date: Mar 2003 Posts: 32	Just finished the rear disc conversion on my 86GT using sn95 front and rear. I did use a prop valve from Maximum Motorsports along with the plug kit for the stock M/cylinder. Check out www.matt90gt.com site for all the info related to this swap. What are you going to use for this swap?

07-20-2003, 12:44 PM	#8
jrgoffin Registered Member Join Date: May 2002 Location: The Midwest Posts: 79	I added the 2-port aluminum SVO MC to mine, but it also has the 73mm front calipers. Works great, but I have also heard of others staying with the stock MC/PV (in similar fashion to the '93 Cobra) and having that work fine as well. I wrote a real nice tech article for another site that has lots of pictures and a parts list - if anyone is interested, I'd be happy to pass it along! Joe jrgoffin@netzero.net __________________ '90 LX Too many mods... Rear-Disc tech

07-21-2003, 10:06 AM	#9
KG88GT Registered Member Join Date: Sep 2001 Location: Pueblo, CO, USA Posts: 43	Just a quick post to say thanks for the help. Now it is time to hit the yards to get some parts. Thanks again KG88GT

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
doing cobra rear swap--- do i need to change master cylinder?	dragstang86	Windsor Power	2	08-03-2003 07:59 AM
Brake upgrade - master cylinder?	LowDown	Windsor Power	7	07-09-2002 08:04 AM
master cylinder and prop valve question	shelby2	Classic Mustangs	1	07-05-2002 05:32 PM
Rear disc brakes in an 88GT upgrade	KG88GT	Windsor Power	3	10-24-2001 05:54 PM
66 master cylinder upgrade	lylesponycar	Classic Mustangs	3	11-05-2000 08:32 PM